Converting PLC instruction sequence into logic circuit: A preliminary study

By implementing a control program with hard-wired logic using reconfigurable devices (e.g., FPGA), a flexible and highly responsive system can be realized. This new system also contributes to securing intellectual property, while reducing implementation space and cost. This study outlines a converter that translates PLC instruction sequence into logic description. A design framework is also described, which integrates control logic and peripheral functions on an FPGA chip. A productive ladder program was examined with Mitsubishi Electric FX2N PLC and Altera APEX20KE FPGA, and the derived logic designs were shown to fit into an actual FPGA chip. A straightforward sequential design was estimated to be 79 times faster than PLC, while a performance-oriented flat design was estimated to be 43 times faster than sequential design (i.e., 3397 times faster than PLC)